1. Field of the Invention
The present invention concerns a projection exposure device for exposing a fine pattern over a large area on a member to be exposed and, in particular, to a lateral type projection exposure device.
2. Description of the Prior Art
The projection exposure device of the aforementioned type has been described, for example, in Japanese Utility Model Laid-Open Sho 62-152293, 62-158824, 63-155637, 64-37044, 64-54335 and Hei 1-97288, each of which was previously proposed by the assignee of the present invention.
Each of the prior art devices has a vertical type structure in which a member to be exposed (hereinafter referred to as an exposure member) is disposed in a horizontal direction and a projection lens, a mask and a light source are sequentially disposed on a vertical optical axis relative to the exposure member and can conduct an accurate exposure to the exposure member having a relatively large area, such as a shadow mask of a display or a liquid crystal device.
However, in the projection exposure device of the known type described above, since the exposure member is placed in the horizontal direction with the optical axis being in the vertical direction, there has been a problem that distortion tends to be caused in the exposure member as the exposing area of the exposure member is enlarged thereby making it difficult to form an exposure pattern at a high accuracy.
For overcoming such a problem there has been proposed an exposure device as described in Japanese Patent Laid-Open Hei 1-312547 in which a continuous metal strip having a photosensitive layer coated on each of the surfaces (exposure member) is transported in a vertically standing direction and a shadow mask pattern is exposed in an intimate contact by a exposure device main body opposing a pair of vertically disposed negative dry plates to the continuous metal strip.
However, in the exposure device for the contact exposure proposed above, although the distortion of the exposure member by its own weight can be prevented by transporting the exposure member while standing it vertically, it is necessary to form both of the negative dry plates and the exposure member in substantially the same size due to the employment of the both face contact exposure system. Accordingly, problems arise in that high accuracy exposure of a plurality of patterns of the exposure member having a large area by a step-and-repeat system is impossible, there is an inevitable limit for forming a plurality of patterns at a high accuracy on a negative dry plate of a large area, and exposure of an exact pattern is difficult since heat expansion of the negative dry plate is caused by the heat generated from the light source.